Unpublished letters by William Wordsworth's sister-in-law offering fresh insights into the life and times of the archetypical Lake District poet have been handed over to The Wordsworth Trust.

Some 156 letters penned by the sharp-witted Priscilla Lloyd, wife of Wordsworth's brother Christopher, were donated to the trust on Friday as the first foundations were laid for its new £3.15 million building, which will house its growing literary collection.

"I'm particularly pleased these letters are going to the centre," said their former custodian Patrick Tolfree, a direct descendant of Christopher Wordsworth. "It's going to enable people from all over the world to come and study them and anything related to the Romantic movement."

To mark the double celebration, former culture secretary Chris Smith MP and Heritage Lottery Fund chairman Liz Forgan levelled off a patch of ceremonial concrete before a crowd of hard-hatted dignitaries next to a great hole where the foundations of the new centre are being put in place.

The much-anticipated building in the grounds of Wordsworth's Grasmere home, Dove Cottage, will offer improved research facilities, a conservation area, a specialist storage basement and a round turret dubbed The Voice Box' providing space for poetry readings. It has been christened The Jerwood Centre' after the charitable trust that donated £500,000 to the project.

"It will enable us to keep, to preserve, to hold and to make accessible the greatest collection of Wordsworth and Romantic material in the world," said Mr Smith, who is chairman of the Wordsworth Trust on top of his parliamentary day job.

Meanwhile, Ms Forgan described the trust as the worthy recipient of £2.5m of heritage lottery cash a huge donation only matched in Cumbria by its contribution to Blackwell, Windermere's Arts and Crafts House.

Alongside the trust's existing collection of 50,000 manuscripts, books, letters and paintings, the Lloyd letters will add a new twist to understanding the 19th century poet.

"It is quite an enigma whether WW is married or not," wrote Priscilla Lloyd in 1802 after Wordsworth returned from his honeymoon with Mary Hutchinson. "W appeared in wretchedly low spirits and in no respects bridegroom like."

As to whether such observations hint at W's romantic entanglement with his sister Dorothy is a matter for speculation but Mr Tolfree was adamant that they did not.

The letters are an interesting study in themselves of Mrs Lloyd who lived a passionate life, lobbying her father for six years in numerous eloquent notes to allow her to marry out of her family's Quaker faith to Christopher Wordsworth. But after successfully securing the marriage, happiness was fleeting and she died aged 34 following a series of difficult pregnancies.

Literary enthusiasts eager to draw on such historical stories will be able to take advantage of the new Jerwood Centre.

Construction is already well under way to excavate around 2,000 cubic metres of soil to make room for a huge basement to house the priceless collections in a humidity-controlled environment. Metal pins 30ft long have already been driven into the hillside around the site to hold it back, while reinforced concrete will be used to sure up the foundations and ensure the Jerwood building does not get pushed into Grasmere.

Once the foundations are in place, around 35 people are expected to be hired including local construction workers to build the centre from slate trucked in from Elterwater.

"That expertise is still in the Lakes," said contracts manager Damian Teal of site developers Kier Northern.

The building should be open by April 2004, when next year's daffodils are fluttering and dancing in the breeze.

April 10, 2003 10:00